6,560 research outputs found
How Can We Obtain a Large Majorana-Mass in Calabi-Yau Models ?
In a certain type of Calabi-Yau superstring models it is clarified that the
symmetry breaking occurs by stages at two large intermediate energy scales and
that two large intermediate scales induce large Majorana-masses of right-handed
neutrinos. Peculiar structure of the effective nonrenormalizable interactions
is crucial in the models. In this scheme Majorana-masses possibly amount to
O(10^{9 \sim 10}\gev) and see-saw mechanism is at work for neutrinos. Based
on this scheme we propose a viable model which explains the smallness of masses
for three kind of neutrinos .
Special forms of the nonrenormalizable interactions can be understood as a
consequence of an appropriate discrete symmetry of the compactified manifold.Comment: 30-pages + 6-figures, LaTeX, Preprint DPNU-94-02, AUE-01-9
Transition density of diffusion on Sierpinski gasket and extension of Flory's formula
Some problems related to the transition density u(t,x) of the diffusion on
the Sierpinski gasket are considerd, based on recent rigorous results and
detailed numerical calculations. The main contents are an extension of Flory's
formula for the end-to-end distance exponent of self-avoiding walks on the
fractal spaces, and an evidence of the oscillatory behavior of u(t,x) on the
Sierpinski gasket.Comment: 11 pages, REVTEX, 2 postscript figure
Complete Genome Sequences of Arcobacter butzleri ED-1 and Arcobacter sp Strain L, Both Isolated from a Microbial Fuel Cell
Arcobacter butzleri strain ED-1 is an exoelectrogenic epsilonproteobacterium isolated from the anode biofilm of a microbial fuel cell. Arcobacter sp. strain L dominates the liquid phase of the same fuel cell. Here we report the finished and annotated genome sequences of these organisms
Manifestations of fine features of the density of states in the transport properties of KOs2O6
We performed high-pressure transport measurements on high-quality single
crystals of KOs2O6, a beta-pyrochlore superconductor. While the resistivity at
high temperatures might approach saturation, there is no sign of saturation at
low temperatures, down to the superconducting phase. The anomalous resistivity
is accompanied by a nonmetallic behavior in the thermoelectric power (TEP) up
to temperatures of at least 700 K, which also exhibits a broad hump with a
maximum at 60 K. The pressure influences mostly the low-energy electronic
excitations. A simple band model based on enhanced density of states in a
narrow window around the Fermi energy (EF) explains the main features of this
unconventional behavior in the transport coefficients and its evolution under
pressure
Kondo Effect of a Magnetic Ion Vibrating in a Harmonic Potential
To discuss Kondo effects of a magnetic ion vibrating in the sea of conduction
electrons, a generalized Anderson model is derived. The model includes a new
channel of hybridization associated with phonon emission or absorption. In the
simplest case of the localized electron orbital with the s-wave symmetry,
hybridization with p-waves becomes possible. Interesting interplay among the
conventional s-wave Kondo effect and the p-wave one and the Yu-Anderson type
Kondo effect is found and the ground state phase diagram is determined by using
the numerical renormalization group method. Two different types of stable fixed
points are identified and the two-channel Kondo fixed points are generically
realized on the boundary.Comment: 15 pages, 17 figures, J. Phys. Soc. Jpn. 80 (2011) No.6 to be
publishe
Newly developed EMF cell with zirconia solid electrolyte for measurement of low oxygen potentials in liquid Cu-Cr and Cu-Zr alloys
In order to measure the very low oxygen potential by use of stabilized zirconia solid electrolyte emf method, a new cell construction was devised. The idea was based on Janke but a zirconia rod was used instead of the zirconia crucible which contacts liquid alloy electrode. The cell was used for determination of the oxygen potentials in liquid dilute Cu-Cr and Cu-Zr alloys. The reference electrode was Cr,Cr2O3. Emf measurements were performed in the temperature range of 1400-1580K and composition range of 0.198-3.10at%Cr-Cu alloys, and 1380-1465K, 0.085-0.761at%Zr-Cu alloys. The composition of liquid alloys were determined by picking up from the liquid alloys and ICP analysis. By use of the newly devised cell construction in this study, stable emf values were obtained at each temperature and alloy composition. Emf values were corrected by using the parameter for electronic contribution of the YSZ. Activity of Cr obeys Henry’s law and activity coefficient at infinitely dilute alloys of Cr in Cu-Cr alloys are: lng0 Cr =(3.80 at 1423K), (3.57 at 1473K), (3.38 at 1523K) and (3.20 at 1573K). At 1423 K activity coefficient of Zr at infinitely diluted alloy is lnγo Zr = -4.0
Topology, Hidden Spectra and Bose Einstein Condensation on low dimensional complex networks
Topological inhomogeneity gives rise to spectral anomalies that can induce
Bose-Einstein Condensation (BEC) in low dimensional systems. These anomalies
consist in energy regions composed of an infinite number of states with
vanishing weight in the thermodynamic limit (hidden states). Here we present a
rigorous result giving the most general conditions for BEC on complex networks.
We prove that the presence of hidden states in the lowest region of the
spectrum is the necessary and sufficient condition for condensation in low
dimension (spectral dimension ), while it is shown that BEC
always occurs for .Comment: 4 pages, 10 figure
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